共查询到20条相似文献,搜索用时 406 毫秒
1.
We construct a new broad class of gauge-invariant nonlinear sigma models in N=2 superspace. The dimensional reduction of the theories obtained to d=2 leads to N=4 nonlinear sigma models which are devoid of ultraviolet divergence in all orders of perturbation theory.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 49–53, February, 1989. 相似文献
2.
A. V. Kotikov 《Physics of Particles and Nuclei》2010,41(6):951-953
We show results for the universal anomalous dimension γuni(j) of Wilson twist-2 operators in the $
\mathcal{N}
$
\mathcal{N}
= 4 Supersymmetric Yang-Mills theory in the first three orders of perturbation theory. These expressions are obtained by
extracting the most complicated contributions from the corresponding anomalous dimensions in QCD. 相似文献
3.
The Wess-Zumino model on N=1/2 nonanticommutative superspace, which contains the dimension-6 term F3, is shown to be renormalizable to all orders in perturbation theory, upon adding F and F2 terms to the original Lagrangian. The renormalizability is possible, even with this higher-dimension operator, because the Lagrangian is not Hermitian. Such deformed field theories arise naturally in string theory with a graviphoton background. 相似文献
4.
We prove conjecture due to Erickson-Semenoff-Zarembo and Drukker-Gross which relates supersymmetric circular Wilson loop operators in the N=4{\mathcal N=4} supersymmetric Yang-Mills theory with a Gaussian matrix model. We also compute the partition function and give a new matrix model formula for the expectation value of a supersymmetric circular Wilson loop operator for the pure N=2{\mathcal N=2} and the N=2*{\mathcal N=2^*} supersymmetric Yang-Mills theory on a four-sphere. A four-dimensional N=2{\mathcal N=2} superconformal gauge theory is treated similarly. 相似文献
5.
Euclidean symmetric integration, previously proposed for the SU(N) Yang-Mills theory in the limit of large N, is used to study the propagators in the Schwinger model and the massive vector-meson model in two dimensions. The result of summing the perturbation series agrees with the exact solution in each case. Therefore, perturbation theory is here capable of dealing with non-analytic behaviour in the coupling constant. 相似文献
6.
We prove a generalization of Kirchhoff's matrix-tree theorem in which a large class of combinatorial objects are represented by non-Gaussian Grassmann integrals. As a special case, we show that unrooted spanning forests, which arise as a q-->0 limit of the Potts model, can be represented by a Grassmann theory involving a Gaussian term and a particular bilocal four-fermion term. We show that this latter model can be mapped, to all orders in perturbation theory, onto the N-vector model at N=-1 or, equivalently, onto the sigma model taking values in the unit supersphere in R(1|2). It follows that, in two dimensions, this fermionic model is perturbatively asymptotically free. 相似文献
7.
Using the shell model wave functions, we have studied quadrupole moments of medium-weight and heavy hypernuclei, and obtained
the shell model values of quadrupole moments of NΛ systems ( N = p and n). With the use of the first-order perturbation
theory, we have also estimated the configuration mixing effects on quadrupole moments of these NΛ hypernuclei. We show that
the hyperon-induced configuration mixing effects are small and the nucleon-induced configuration mixing effects are large
in many cases.
Received: 22 February 2000 / Accepted: 2 August 2000 相似文献
8.
We present results for the universal anomalous dimension γ
uni(j) of Wilson twist-2 operators in the = 4 supersymmetric Yang-Mills theory in the first four orders of perturbation theory.
The text was submitted by the authors in English. 相似文献
9.
In order to characterize the spin-spin exchange interactions responsible for the Type-E' antiferromagnetic order in inhomogeneous RNiO3 perovskites (R=Y or rare earth), the pressure dependence of the Néel temperature T(N) was systematically measured for samples with T(N)相似文献
10.
11.
We use the gauge-gravity duality conjecture to compute spectral functions of the stress-energy tensor in finite-temperature N = 4 supersymmetric Yang-Mills theory in the limit of large N(c) and large 't Hooft coupling. The spectral functions exhibit peaks characteristic of hydrodynamic modes at small frequency, and oscillations at intermediate frequency. The nonperturbative spectral functions differ qualitatively from those obtained in perturbation theory. The results may prove useful for lattice studies of transport processes in thermal gauge theories. 相似文献
12.
Kay Jörg Wiese 《Journal of statistical physics》1998,93(1-2):143-154
We present a simple argument to show that the β-function of the d-dimensional KPZ equation (d≥2) is to all orders in perturbation theory given by $\beta (g_R ) = (d - 2)g_R - [2/(8\pi )^{d/2} ]{\text{ }}\Gamma (2 - d/2)g_R^2 $ Neither the dynamical exponent z nor the roughness exponent ζ have any correction in any order of perturbation theory. This shows that standard perturbation theory cannot attain the strong-coupling regime and in addition breaks down at d = 4. We also calculate a class of correlation functions exactly. 相似文献
13.
We argue that recent results in string perturbation theory indicate that the four-graviton amplitude of four-dimensional N=8 supergravity might be ultraviolet finite up to eight loops. We similarly argue that the h-loop M-graviton amplitude might be finite for h<7+M/2. 相似文献
14.
G. Benfatto M. Cassandro G. Gallavotti F. Nicolò E. Olivieri E. Presutti E. Scacciatelli 《Communications in Mathematical Physics》1978,59(2):143-166
We study, in the context of the Markov hyerarchical fields (d=2, 3) the role of the Markov property, of formal renormalization and of formal positivity. We determine upper and lower bounds for the ground state energy and discuss their relation with the perturbation theory series.This work has been partially supported by I.N.F.N., G.N.F.M., and G.N.S.M. 相似文献
15.
J. S. Levinger 《Annalen der Physik》1997,509(5):395-402
Huang and Yang replace a hard core of radius c by their pseudopotential (HYPP), which can be used in perturbation theory. I show that HYPP and boundary value perturbation theory give the same energy shift, to first order in c. I model a two-body potential as an oscillator potential (angular frequency ω) and a hard core. For an A-body system, the ratio of the first order energy correction to the unperturbed energy is 0.448 A3/4 c a, where a = (M ω/2h)1/2. 相似文献
16.
A new nonlinear -model with N=4 supersymmetry in d=2 is constructed in terms of a N=2 tensor multiplet in d=4. Four equivalent formulations of the theory in superspace are obtained. The component structure of the model is considered by means of the Legendre transformation.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 70–74, September, 1987. 相似文献
17.
A. D. Gurchumeliya E. P. Ivanova M. A. Tsirekidze T. A. Tsirekidze 《Russian Physics Journal》1985,28(10):852-858
Perturbation theory together with a model zeroth-order approximation is used to calculate the energy levels of the 4s4p, 4p2, 4s4d, 4p4d, and 4s5s configurations of a number of Zn-like ions with nuclear charges in the range Z = 36–50. The zeroth-order functions of the approximation are the wavefunctions of an electron that moves in the field of the model core potential. The parameters of the model potential are found by using the empirical energy levels of the Cu like ions. The calculation is carried out to first order in the perturbation theory together with the inclusion of an effective account of the higher order corrections. The calculation is accurate to a fraction of a percent.Deceased.Translated from Izvestiya Vysshikh Uchebnyh Zavedenii, Fizika, No. 10, pp. 99–105, October, 1985.The authors thank K. G. Oganov for help in carrying out the numerical work. 相似文献
18.
Kruk D Kubica A Masierak W Privalov AF Wojciechowski M Medycki W 《Solid state nuclear magnetic resonance》2011,40(3):114-120
A general theory of field dependent spin-lattice relaxation for nuclei of the spin quantum number 1/2 (1H, 19F, 13C) caused by dipole-dipole interactions with neighboring quadrupolar nuclei (nuclei possessing a quadrupolar moment) is presented. The theory is valid for arbitrary motional conditions and should be treated as a quadrupolar counterpart of the paramagnetic relaxation enhancement theory. When the energy level splitting of the dipolar spin (I=1/2) matches one of the transition frequencies of the quadrupolar nuclei one can observe a local enhancement of the dipolar spin relaxation (referred to as "quadrupolar peaks"). To see such effects the dynamics modulating the spin interactions has to be relatively slow. This brings the system beyond the validity range of perturbation approaches and requires the stochastic Liouville equation to be applied. The presented theory describes the quadrupolar relaxation enhancement (QRE) for an arbitrary spin quantum number of the quadrupolar nuclei and includes the asymmetry of the quadrupolar coupling. It has been applied to interpret the shape of magnetization curves (amplitude of 1H magnetization versus magnetic field) for the molecular crystal [C3N2H5]6[Bi4Br18] ([C3N2H5]-imidazolium). The magnetization curves show several dips (local minima) attributed to 1H-14N quadrupolar relaxation enhancement effects. In addition, as a limiting case a perturbation approach to QRE has been presented and its validity conditions have been discussed. 相似文献
19.
Masashi Wakamatsu 《Nuclear Physics A》1979,329(3):381-406
The effects of the Δ(3-3) resonance components on the binding energy of 4He are studied within the framework of reaction matrix theory. In this approach, the Δ -configurations in 4He are introduced in terms of the NΔ transition potential by solving the reaction matrix equation and thus it goes beyond perturbation theory with the NΔ transition potential. Not only the two-body cluster energy but also the three-body cluster energy containing Δ-configurations are calculated. 相似文献
20.
M. Frink U. -G. Meißner I. Scheller 《The European Physical Journal A - Hadrons and Nuclei》2005,24(3):395-409
We calculate the baryon octet masses to fourth order in chiral perturbation theory employing dimensional and cut-off regularization. We analyze the pion and kaon mass dependences of the baryon masses based on the MILC data. We show that chiral perturbation theory gives stable chiral extrapolation functions for pion (kaon) masses below 550 (600) MeV. For the pion-nucleon sigma term we find
(0) = 39.5...46.7MeV. 相似文献